Transmission Between Neurons

Question 1

An excitatory input is called…

Answer 1

Excitatory post synaptic potential EPSP

Question 2

The synapse is…

Answer 2

A small gap between neurons

Electron microscopes let us see individual synapses

Question 3

A neurotransmitter is…

Answer 3

A chemical signal carrying information between neurons. It is released from pre synaptic neuron to the post synaptic neuron

Question 4

A vesicle is…

Answer 4

A sack full of neurotransmitter found in each bouton/terminal

Question 5

The synapse in action…

Answer 5

1) AP arrives at the bouton of presynaptic cell which opens the calcium ca2+ ion channels
2) calcium causes vesicles to fuse with cell membranes (exocytosis) and neurotransmitter is released into synaptic cleft
3) the neurotransmitter diffuses across the cleft and binds to receptor on the post synaptic neurons which can trigger a new AP

Question 6

Neurotransmitter can be removed from the synaptic cleft by…

Answer 6

Diffusion
Reuptake - transport moves neurotransmitter back into presynaptic neuron which uses energy
Deactivation - enzyme breaks neurotransmitter down into parts, which happens in the synaptic cleft

Question 7

Raman Y Cajal

Answer 7

Nobel prize 1906

Proposed synapses

Question 8

Bernard Katz

Answer 8

Nobel prize 1970

Synapse chemical

Question 9

Inhibitory neurotransmitter

Answer 9

GABA

Question 10

Excitatory neurotransmitters

Answer 10

Glutamate
Acetylcholine
Serotonin
Dopamine

Question 11

Non primary neurotransmitter

Answer 11

Neuro modulators - modulate transmission of information

Question 12

Action potentials are…

Answer 12

Generated in the axon hillock. They move down the axon and their amplitude is always the same
Several action potentials arrive at the dendrite which triggers a change in the postsynaptic membrane causing an electrical change in membrane potential

Question 13

Acetylcholine

Answer 13

Is found in the brain and neuromuscular junction. It binds to nicotinic receptors in the post synaptic neuron. It increases the membrane potential
It is fast (ionotropic) and excitatory
Nicotine also binds at nicotinic receptors

Question 14

A neuromuscular junction is…

Answer 14

Where the neuron joins muscle to activate the muscle

Curare blocks the action of ACh here and paralyses prey

Question 15

Glutamate

Answer 15

Found in the CNS and the brain. It is the main carrier of excitatory neurotransmission
ACh is a primary neuromodulator here

Question 16

Serotonin

Answer 16

Is found in the brain
It binds to receptor which triggers G protein which activates a 2nd messenger which opens on channels
It is slow (metabotropic) and excitatory

Question 17

GABA (gamma aminobutyric acid)

Answer 17

Is found throughout the brain. Binds to fast and slow GABA receptors which opens Cl- ion channels and decrease membrane potential.
GABA inhibits neurons and reduces the likelihood to fire at AP

Question 18

Neurotransmitters and drugs

Answer 18

Nicotine - nicotinic acetylcholine receptors
Alcohol - GABA serotonin dopamine NMDA
amphetamines and cocaine - dopamine 
Prozac - serotonin
L-Dopa - dopamine
Diazepam - GABA 
Dinepezil - acetylcholine

Question 19

Excitation - glutamate, serotonin

Driven by osmosis gradient

Answer 19

Sodium and calcium enter neuron. EPSP. Influx of sodium - membrane potential increases and AP more likely

Question 20

Inhibition - GABA

Driven by osmosis gradient

Answer 20

Potassium leaves and Chloride enters. IPSP. Influx of chloride and membrane potential decreases making AP less likely

Question 21

Donald O. Hebb

Answer 21

Axon of cell A near enough to excited cell B and often takes part in firing it - growth process or metabolic change takes place in one or both cells so A’s efficiency, as a cell firing B, increases

Question 22

Hebbian learning rule

Answer 22

Synchronised activation of two neural pathways leads to strengthening of the previously ineffective one by enhancing their synaptic efficiency or gain
Long term potentiation is a prominent mechanism for associative learning